Dental chair and the like



Aug' .26, 1947 D. J. BlNus. 2,426,336

DENTAL CHAIR AND THE LIKE l I t www David Jin'us m 99m wm@ www -2 Sheets-Sheet 2 l D. J. BINUS DENTAL CHAIRVAND THE LIKE Filed Feb. 4, 1944 avlld Bin us @M 5g/w46 76,44%

Aug. l26, 1.947.

Patented Aug. 26, 1947 UNITED STATES PATENT `OFFICE DENTAL CHAIR AND THE LIKE David J. Binus, Canton, Ohio, assignor to The Weber Dental Manufacturing Company, vCanton, Ohio, a corporation of Ohio Application February 4, 1944, Serial No. 521,046

11 Claims.

The i-nvention relates to dental chairs and the like having spring means coacting with the chair parts to assist in lifting the chair back from a lowered position, particularly when supporting a patient. l

Usual spring means for coacting with the parts of a dental chair and the like to assist in lifting the chair back, have required considerable reconstruction of the parts of a chair of usual design without such spring means, and are of relatively complicated construction, andare relatively dif-- ficult to adjust `to attain the desired spring pressure.

Moreover, some spring means incorporated in dental chairs and the like kfor facilitating the lifting `o-f the chair back -have been so located and have had constructions and arrangements which have tended to catch the clothes and vloody parts of .patients seated in the chairs, which is very undesirable.

The objects of the present invention include the provision of an improved .dental chair and the like having improved spring means for facilitating the lifting of the chair back .and which vmay be incorporated in a dental chair and the like .of usual design with a minimum `reconstruction of the parts of the chair.

Further objects of the present invention .include the provision of such a dental chair and the like in which the spring means are located and concealed so that the spring means cannot become entangled or engaged with the clothes or body parts of a patient seated in the chair, and .so that the spring means are at the same time easily accessible for adjustment.

Further objects of the present vinvention'include the `provision of such an improved dental chair with spring means for facilitating lifting of the chair back, and which is simplified in construction and in the arrangement and cooperation of `its 'parts so that it may be manufactured and maintained `with facility and economy.

The foregoing and other objects are attained "by the chair apparatus and the like, parts, members, combinations, and sub-combinations which comprise the present invention and the nature of which is set forth in the following general statement, and preferred embodiments of which `together -w-ith their mode of use are set forth in `the Afol-lowing description, and which are particularly and distinctly pointed out and lset `forth in the appended claims forming part hereof.

'The nature of the present invention may -be stated in general terms as including in a dental chair and the 1li-ke, linkage apparatus including a plurality of relatively movable bar links, some of which are pivotally connected `with each other, and preferably constituting a four-bar linkage, and spring means operatively associated with at least `one bar link or extension thereof and another part of the linkage for tending to `swing the .one bar link in one direction, and one of the bar links preferably including walls forming a housing for the spring means.

By way of example, embodiments of the improved chair, in the 'form of dental chairs with swinging backs and improved spring means for facilitating lifting -of the backs, are illustrated in the accompanying drawings forming part hereof, in which Figure 1 is a fragmentary side elevation with portions in section of a dental chair including vone embodiment of the present improvements;

Fig. 2, a View similar to Fig. 1 showing another dental chair including a, second embodiment of the present improvements;

Fig. 3, a similar view of detached portions of the back of the chair of Fig. 2; and

Fig. 4, an enlarged view .of detached portions of Fig. `3 looking .in the `direction of .the arrows 1 -4.

Similar numerals refer to similar parts through- .out the drawings.

The improved dental chair illustrated in Fig. 1 is indicated generally by H and includ-es a base i2 having operatively -mounted therein in a usual manner elevator means, not shown, by which the chair seat .frame I3 andthe parts carried thereby are raised 4and lowered.

The chair seat frame I3 has at each side a .pivotal connection `I4 yat its rear with the lower end of a chair back frame 15.

The chair Il also `includes at each side an upper bar link in the form .of an arm H5 having a pivotal connection Il at its rear `end with a rear bar link in the `form of an 'upwardly extending bracket i8 on the ,chair back frame l5. The front end of each arm H5 has ra pivotal connection I9 with the upper emi of a front bar link 2.0 which has a pivotal connection 2l at its lower end with the lfront end vof the .seat frame i3, which is itself a lower bar link.

The pivotally connected upper, front, lower, .and rear bar link-s as thus .set forth `,constitute a fourbar linkage.

For the purposes of the present improvements, .each upper arm .I6 includes a lower upwardly opening housing trough 22 having van upper elongated removable top or `cover 23 shown in elevatudinal vertical section, and the lower flat face of the top or cover 23 seating on the upper flat edges of the box-like trough 22. Within the compartment 24 of the housing trough 22 and intermediate its ends, there is located a transversely extending web 25 having a central opening 25| formed therein. The housing trough 22 includes an elongated lower wall 26 in the forward end of which there is formed an opening 2l at each side of which depends a tongue 28 forming part of the pivotal connection I9.

In the pivotal connection I9, the upper end of the arm 2B extends between the tongues 28, and a pivot pin 29 extends through registering apertures in the upper end of the bar link 2B and the tongues 28.

For the purposes of the present improvements the upper end of the bar link 20 extends upwardly above the pivot pin 29 through the opening 2'! into the forward end of the housing trough compartment 24, as a relatively short lever extension 30.

Improved spring means indicated generally by 3| are located in the elongated compartment 24 of the housing trough 22, and are operatively interposed between one O f the housing walls, as shown, the transverse web 25 and the upper lever extension 39 of the link 20. As shown, the improved spring means 3| includes a rod 32 extending through the web opening 25| and having at its front end, portions of ball and socket joint means indicated generally by 33 between the rod 32 and the lever extension 3U.

As shown, the ball and socket joint means 33 includes a spherical head 34 on the front end of the rod 32, and a hemispherical seat 35 formed in the rear face of the upper lever 30 of the link 29, the spherical head fitting in the hemispherical seat. At the rear of the head 34, the rod 32 has threads 36 formed thereon, and a nut 3'! is screwed upon the threads 36.

A compression spring 33 is interposed between the front of the web 25 and the rear of the nut 3T. As shown the compression spring 38 is an elongated helical compression spring through the central elongated aperture of which extends the rod 32.

The spring means 3| functions to urge the lever extension 30 and front link 20 forwardly.

The thread 36 and nut 3l combination constitutes adjusting means for varying the extended pressure of the spring means 3|.

The chair back frame I extends rearwardly and has operatively associated therewith and mounted thereon usual dental chair back parts indicated generally by 39 and headrest parts indicated generally by 40.

In operation, when the chair back 39 is swung backwardly the four-bar linkage action of the pivotally connected parts causes the upper arm I6 to lower and the lever extension 39 to swing rearwardly and load the compression spring 38, whether or not a patient is seated in the chair and is supported by the chair back.

In a dental chair, clamp means are usually provided for controlling the upward and downward swinging of the back, and for locking the back in any desired position. Accordingly, when a patient is occupying the chair with the back lowered, and thus is in a reclining position, the loaded spring 38 acting as a part of the spring means 3| and the other four-bar linkage parts, serve to provide part of the force necessary to lift the back and the patient reclining theI'COn,

4 by suitable releasing action of the back clamp means, not shown.

The improved chair as thus set forth may be incorporated in a usual dental chair which may have substantially the same parts as those shown with the exception of the construction and arrangement of the upper arm IS, the spring means 3|, and the lever extension 30.

The spring means 3| and the lever extension 33 are entirely enclosed in the housing arm I9, and there is thus no danger of catching or entangling body parts or clothing of a patient occupying the chair.

In Figs. 2 to 4, inclusive, a second improved dental chair is indicated generally by and as shown includes parts identical with the parts of the improved dental chair with the addition, in the clamp means 4| and cooperating therewith, of second spring means indicated generally by 42 which may be used independently of the rst spring means 3|, but which preferably as shown come into action after the chair back 39 and the four-bar linkage parts have been swung back to the position shown in Fig. 2, where dimensional limitations of the housing arm E6 and the angular relation of the bars of the four-bar linkage may produce insufficient forward thrust by the loaded spring 38.

Under these conditions, it is desirable to provide the second spring means 42 for producing an added upward push on the back 39 and the fourbar linkage parts, when the clamp means 4| is released at the position of the parts shown in Fig. 2.

The back 39 of the chair has the chair back frame |5 and the pivotal connection |4 as aforesaid with the chair seat frame I3. The clamp means 4| includes a lower preferably externally cylindric slide member 43 having a pivotal connection 44 with the rear of the chair seat frame I3, the pivotal connection 44 being offset a substantial distance to the rear of the pivotal connection I4 of the four-bar linkage.

The clamp means 4| furthermore includes an upper elongated slide and housing member 45 which has at its lower end a preferably cylindric slide bore 43 in which is slidably tted the slide member 43.

The lower end of the housing member 45 furthermore has operatively mounted therein and associated with the lower slide member 43, a usual clamp bar 41 having a clamp bore 43 through which the slide member 43 extends, the clamp bar 41 having a loose pivotal mounting indicated generally by 49 at one side of the slide member 43, and as shown at the same side of the slide member 43, compression spring means 49' urge the clamp bar 41 upwards about the pivotal connection 49, whereby the telescoping slide members 43 and 45 are automatically clamped at any position of the rearward swinging of the back frame |5 such as that shown in Fig. 2, wherein the slide member 43 is telescoped into the slide member 45.

The loose pivotal mounting 49, as shown in Fig. 4, includes a notch 11S-I at the end of the clamp bar 41 below the spring 49', and a shouldered pin 49-2, parallel with the cylindric slide member 43, has its ends mounted in opposite walls of the lower end of the housing member 45, and the reduced central shank of the shouldered pin 49-2 extends with clearance through the clamp bar end notch 49-|. The opposite shoulders 4.9-3 of the pin 49--2 at opposite ends of its assesses reduced central shank, provide 'fulcrums for the opposite aces fof the clamp :bar f4.1.

.lin a usual manner., :the upper fend nf the .slide member 45 has a :pivotal connection 5t with the upper fend ofthe fback frame t5.

'The Aclamp :means 4i also includes usual releasing lever .means 52 operative 'to swing the clamp bar dl towards the lower end fof the slide member llt for .releasing the 'clamping gf :the slide members 1%5 and 43 with .each other Yand thus permitting backward swinging fof the back ffra'me 'l5 and back 39.

'The parts .of the clamp means .fllf :as described up to ith-is point :are of Ausual construction, VVor may be of Vany other usual construction wherein two .members :are :sllidably associated with each other and have releasablfe automatic clamp means Afor clamping the .slide members at any desi-red position :against movement in one direction.

In the illustrated clamp means el, the 'coaction of the parts is such that by reason of the pressurebetween the clamp bore e8 and thercylindric slide member 'd3 produced by the spring 65" when the parts are in their clamping positions shown in 4, the back frame t|`5 and vback 39 will remain lat any position to which they may have been swung. lAt such position the back frame l5 and back '3S .are locked against further swinging or tilting back, but may be pushed up without operating the releasing 'lever `means L52, which are only operated to permit backward swinging.

For the purposes ofthe present improvements, the `slide member 43 is tubular and has an elongated compression spring 53 located in its bore.

In the upper end of the tubular .slide member 413 is `screwed a slide 'bearing E4 .in 'the bore 'of which slidably extends a slide rod '55, having within the bore of the tubular `slide member di@ .an enlarged head 56 operating against the upper Aend of the compressionv spring 53. The lower end of the compression spring 53 operates against the inner end of a pivot bracket 5l which is secured as by screw connection 58 with the lower end of the tubular slide member 43, the .pivot bracket E51 .being part 'of the pivotal connection 4.1!.

The upper end Voi the slide rod 55 extends outwardly through the bearing 54 into 'a -compartment -59 of the Vhousing member d5. When the chair --back 39 .is swung the `upper extremity EB of the :slide rod 55 is located below the opposite upper transverse face AISI of the compartment 59 ,as shown in Figs. 3 and d. When the chair back frame yI-5 and back 319 `are swung to the rear and downwardly to the position shown in Fig. 2, the upper face i5! of the compartment 59 oi' the housing slide member 45 strikes against the upper `extremity [it of the slide rod 55 compressing and loading the spring 53, thereby prouiding in the chair .lll an additional force urging the chair back upwardly when the clamp release lever l52 is operated to release the clamp bar 4l from clamping engagement between the slide members 43 and 45.

As above indicated the spring means indicated generally by 42 operatively associated with the clamp means 4| may be used `independently of the spring `means 3! The embodiments of the present improvements illustrated and described herein are by way of example., and the scope of Vthe present invention is not limited to the same or to the particular Idetails thereof, but .is .commensurate with any and all vnovel subject matter contained herein which may at any time proper-ly under the UnitedStates patent .laws be set .forth in` the claims hereof or `originating herein, and the elements of Lany such claims are :intended to include their reasonable, mechanical and functional equivalents.

wclaim:

`1. In .a dental chair and the like, a seat frame having -at one side a portion forming a lower bar flink, a chair back frame having at the same side a portion with an upwardly `extending bracket Eforming a rear bar link, a pivotal connection between the lower end of the rear bar link and the rear end of the lower .bar link, a f-ront bar link spaced forwardly of the rear bar `link and extending upwardly from the lower bar link, a pivotal connection between the .lower end of the front 'bar link and the front end of the lower bar link, an upper bar link arm spaced above the lower bar link, a pivotal connection .between 4the rear end oi the arm and the upper end of the rear bar link, a pivotal connection between the front .end of the arm and th-e upper `end of the front bar link, walls ofthe upper arm forming an elongated housing having a compartment eX- tending above the upper ends of the front and rear bar links, a lower wall of the arm housing having an opening formed therein, the upper end of the front bar link extending through the opening into the housing compartment and forming an upper lever extension, the housing having a transverse wall within the compartment intermediate the front and rear bar links, and spring means within the housing compartment operatively interposed between the transverse wall and the Ylever extension and urging the lever extension forwardly.

2. In a dental chair and the like, a seat frame, and four-bar linkage means including va side portion ofthe seat frame and an upper arm above the frame side portion and spaced iront and rear link bars, each link bar having a lower pivotal connection with the frame side portion and an upper pivotal connection with the arm, walls of the arm forming a housing having a compartment, low-er wall of the arm housing having an opening formed therein, the front link bar having an upper end extending through the opening into the compartment and forming an upper lever extension, and spring means within the housing compartment and operatively interposed between a Wall Vof the housing and the lever extension and urging the lever extension forwardly.

3. In a dental `chair and the like, 'a seat frame,

'and louf-bar linkage means including a side portion Vof the seat frame and an upper arm above the .frame side portion and spaced front and rear link bars, each link bar having a lower pivotal connection with the frame side portion and an upper pivotal connection with the arm, walls of the arm forming a housing having a compartment, a lower wall rof the arm housing having an opening formed therein, the front link bar having an upper end extending through the opening into the compartment and forming an upper lever extension, andcofmpression spring means within the heusing compartment 4and operatively interposed between :a wall of the housing and the lever ex tension Aand urging the lever extension forwardly.

fl. in `a dental chair .and the like, a `seat frame, ,and four-bar linkage means including a side portion of the seat frame and an upper arm above the 'frame side portion and spaced front and rear link bars, each link bar having a lower pivotal yconnection with the frame side portion and an upper pivotal connection with the arm, walls of the arm forming a housing having a compartment, a lower wall of the arm housing having an opening formed therein, the front link bar having an upper end extending through the opening into the compartment and forming an upper lever extension, and spring means within the housing compartment and operatively interposed between a wall of the housing and the lever extension and urging the lever extension forwardly, walls of the housing arm being separable from each other to permit access to the spring means within the housing compartment.

5. In a dental chair and the like, a seat frame, and four-bar linkage means including a side portion of the seat frame and an upper arm above the frame side portion and spaced front and rear link bars, each link bar having a lower pivotal connection with the frame side portion and an upper pivotal connection with the arm, walls of the arm forming a housing having a compartment, a lower wall of the arm housing having an opening formed therein, the front link bar having an upper end extending through the opening into the compartment and forming an upper lever extension, and spring means within the housing compartment and operatively interposed between a wall of the housing and the lever extension and urging the lever extension forwardly, the spring means including adjustable spring loading means.

6. In a dental chair and the like, a seat frame, and four-bar linkage means including a side portion of the seat frame and an upper arm above the frame side portion and spaced front and rear link bars, each link bar having a lower pivotal connection with the frame side portion and an upper pivotal connection with the arm, walls of the arm forming a housing having a compartment, a lower wall of the arm housing having an opening formed therein, the front link bar having an upper end extending through the opening into the compartment and forming an upper lever extension, and spring means withinthe housing compartment and operatively interposed between a wall of the housing and the lever extension and urging the lever extension forwardly, and a chair back on the rear link bar.

7. In a dental chair and the like, a seat frame, and four-bar linkage means including a side portion of the seat frame and an upper arm above the frame side portion and spaced front and rear link bars, each link bar having a lower pivotal connection with the frame side portion and an upper pivotal connection with the arm, walls of the arm forming a housing having a compartment, a lower wall of the arm housing having an opening formed therein, the front link bar having an upper end extending through the opening into the compartment and forming an upper lever extension, and compression spring means within the housing compartment and operatively interposed between a wall of the housing and the lever extension and urging the lever extension forwardly, and a chair back on the rear link bar.

8. In a dental chair and the like, a seat frame, and four-bar linkage means including a side portion of the seat frame and an upper arm above the frame side portion and spaced front and rear link bars, each link bar having'a lower pivotal connection with the frame side portion and an upper pivotal connection with the arm, walls of the arm forming a housing having a co-mpartment, a lower wall of the arm housing having an opening formed therein, the front link bar having an upper end extending through the opening into the compartment and forming an upper lever extension, and spring means within the housing compartment and operatively interposed between a wall of the housing and the lever extension and urging the lever extension forwardly, walls of the housing arm being separable from each other to permit access to the spring means within the housing compartment, and a chair back on the rear link bar.

9. In a dental chair and the like, a seat frame, and four-bar linkage means including a side portion of the seat frame and an upper arm above the frame side portion and spaced front and rear link bars, each link bar having a lower pivotal connection with the frame side portion and an upper pivotal connection with the arm, walls of the arm forming a housing having a compartment, a lower wall of the arm housing having an opening formed therein, the front link bar having an upper end extending through the opening into the compartment and forming an upper lever extension, and spring means withi-n the housing compartment and operatively interposed between a wall of the housing and the lever extension and urging the lever extension forwardly, the spring means including adjustable spring loading means, and a chair back on the rear link bar.

10. In a dental chair and the like, a seat frame, and four bar linkage means including a side portion of the seat frame constituting a lower link bar, an upper arm constituting an upper link bar above the lower link bar, and spaced front and rear link bars, each front and rear link bar having a lower pivotal connection with the lower link bar and an upper pivotal connection with the upper li-nk bar, and first spring means operatively associated with a pivotally connected pair of the link bars including the front link bar and urging forward movement of the front, upper, and rear link bars, and second spring means operatively associated with a pivotally connected pair of the link bars including the rear link bar for urging the same movement of the front, upper, and rear link bars at a predetermined loading of the rst spring means.

11. In linkage apparatus for a dental chair and the like, a plurality of links, each link having a pivotal connection with at least one other link, first spring means operatively associated with the links having one of the pivotal connections to effect relative pivotal movement of the links, and second spring means operatively associated with the links having another of the pivotal connections to effect relative pivotal movement of the links after action of the first spring means.

DAVID J. BINUS.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 883,446 Brownell May 31, 1908 2,074,653 Larsen Mar. 23, 1937 400,561 Goelet Apr. 2, 1889 159,395 Damm Feb. 2, 1875 708,911 OConnor Sept. 9, 1902 165,498 Ott July 13, 1875 274,877 Baldwin Mar. 27, 1883 316,287 Mead Apr. 21, 1885 1,744,258 Bitzenburger Jan. 21, 1930 1,288,216 Sayles Dec. 17, 1918 1,105,990 Miller Aug. 4, 1914 2,118,690 Whedon May 24, 1938 

